Fastener driving tool with slidable fastener guide

ABSTRACT

An explosive fastener driving tool has an adapter mounted on the muzzle end of the barrel and slidably holds a gas actuated liner for receiving a ram. The liner bears on the washer portion of a fastener while the ram impacts the fastener head to insure that the fastener piercing point is guided for efficient work penetration.

United States Patent [1 91 Oefinger 1 Dec. 4, 1973 FASTENER DRIVING TOOLWITH SLIDABLE FASTENER GUIDE [75] Inventor: Richard W. Oefinger,Shelton,

Conn.

[73] Assignee: USM Corporation, Boston, Mass.

[22] Filed: May 23, 1972 [21] Appl. No.: 256,086

[52] US. Cl. 227/10 [51] Int. Cl. B25c 1/14 [58] Field of Search 227/8,9, 10, ll

[56] References Cited UNITED STATES PATENTS 2,930,042 3/1960 Temple etal 227/l0 3,348,751 lO/l967 Henning ..227/8 Primary Examiner-GranvilleY. Custer, Jr. Attorney-Carl E. Johnson et a].

[57] ABSTRACT 5 Claims, 5 Drawing Figures FASTENER DRIVING TOOL WITHSLIDABLE FASTENER GUIDE BACKGROUND OF THE INVENTION Explosive fastenerdriving tools commonly comprise a housing for a barrel, a firingmechanism and means for energizing the mechanism whereby a cartridge orother charge in the breech end of the barrel may be ignited and theresultant gas directed into the barrel to axially drive a ram forimpacting a fastener. The latter ordinarily has a pointed end and a headend, the head end being struck by the ram to drive the pointed end intoa solid material such as concrete or steel.

The driving forces produced are not always uniform, and neither is theresistance to penetration which may be provided by a structure. Asidefrom the fact that fasteners of different size and shape are employed,the hardness of different fastener receiving structures vary, and theefficiency of explosive driving tools is inconstant. One approach toaccommodating different fastener sizes has been to provide a suitableadapter or guide at the muzzle end of the barrel for directing the ramagainst each fastener head. Also, to enable the tool and a particularfastener to adjust to the varying driving and reactive forces, a washeris often frictionally slidable on the fastener stem.

It is found that in the known tools the driving of washer-carryingfasteners from an adapter by a ram is not reliably effective sincepenetration resistance offered by a hard receiving structure may causethe fastener to bend or break. Moreover, this fastener deformationusually occurs oftener when shorter fasteners are used since they tendmore easily to become cocked, i.e., tilted from coaxial relation withthe ram.

SUMMARY OF THE INVENTION In view of the foregoing it is a primary objectof this invention to provide, in an explosive fastener driving tool ofthe type having a barrel with a telescoping ram, and a tubular adaptercoaxially mounted on the barrel for receiving a fastener to be driven bythe ram, an improved means slidable within the adapter for axiallyguiding the fastener to insure its effective penetration into hardstructure.

Another object of this invention is the provision, in a tool'of the typeaforesaid, of a guide means telescoped between the adapter and the ramand arranged to be concurrently driven therewith by the high velocitygases in the barrel bore, the guide means bearing axially on a washer onthe fastener stem as the ram impacts a head of the fastener peripherallysupported in the guide means-whereby the fastener is stabilized duringpenetration of hard material.

To these ends, and as herein shown, a feature of the invention residesin the combination with a barrel having a bore for axially mounting onthe barrel for receiv-' -ingly accommodating the ram and the fastenerhead,

one end of the liner being subjected to the pressure of the explosivegases bypassing the ram and the other end of the liner engaging thewasher to stabilize the fastener during driving.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other features ofthe invention will now be more particularly described in connection withan illustrative embodiment, and with reference to the accompanyingdrawings thereof, in which:

FIG. 1 is a view in side elevation of an explosive fastener driving toolin uncocked condition, a muzzle end portion being shown in axial sectionto reveal an adapter liner;

FIG. 2 is an enlarged view in axial section of the muzzle portion shownin FIG. 1, a fastener and driving parts now being in ready-to-firecondition;

FIG. 3 is a sectional view showing a conventional adapter and a fastenerimproperly driven due to lack of adequate guidance thereby;

FIG. 4 is a view similar to FIG. 2, the parts now being in drivenposition and the result contrasting with that shown in FIG. 3, and

FIG. 5 is a transverse section taken on the line VV of FIG. 2 andindicating the slidable mounting connection of the muzzle adapter to itsliner.

DESCRIPTION OF PREFERRED EMBODIMENT An explosive fastener driving toolgenerally designated 10 in FIG. 1 comprises a housing 12 having an openside 14 for providing access to load the breech bore of an axiallyslidable barrel 16. It will be understood that a firing mechanism notshown is mounted within a handle portion 18 secured to the housing andhaving a trigger 20. Preferably the tool has its firing mechanism cockedby thrusting the housing 12 relatively muzzleward on the barrel andforcing an adapter 22 (FIGS. 1, 2, and 4) endwise against a work piece Pto be secured to a surface S, for instance of solid steel, wherein afastener F is to be driven.

Actuation of the trigger 20 effects explosion of a suitable charge (notshown) whereby a piston-type ram 24 coaxially slidable in the barrel 16is caused by the explosive gases therein to drive the fastener F throughthe work piece and into the structure S.

The fastener Fmay have a head at one end to be impacted by the ram 24and a pointed end for penetrating the structure. Also the fastener may,though not necessarily, be of the type including a washer W frictionallyslidable axially on the fastener stem as it penetrates the work toprevent overdrive. The washer customarily has a larger diameter than thefastener head and is concentric therewith.

As illustrated in FIG. 3 the conventional type of muzzle adapter shownat 26 allows the washer W and the fastener to be tilted from the drivingaxis on eccentrically engaging the work piece and meeting resistance towork piece penetration. Hence the fastener becomes bent in fishhookmanner and may break. The result is that the fastener is not fullydriven and a relatively lower holding power of uncertain degree isobtained.

The present invention advantageously provides for the adapter 22 to havea coaxial guide or liner 28 of shorter length as will next be described.The adapter 22 is herein shown as having retention in the barrel bymeans of an O-ring 30 seated in mating circumferential grooves, and aretaining ring 32. As a precautionary measure a flat spring clip 34 mayhave inturned diametric end portions 36 in latching relation with ashoulder of the barrel. The adapter 22 has a generally uniform bore 38coaxial with the ram 24 and an enlarged, slightly tapered mouth portionfor frictionally accommodating the washer W. Coaxially telescopedbetween the adapter 22 and the ram 24 is the liner 28 having an enlargedmuzzle end 40 for bearing on the washer W, a head end 42 in which an endof the ram 24 is initially received, and a flat side portion 44 forslidably receiving a spring pin 46 partly nested in a transverse boreformed in the adapter 22 as shown in FIG. 5. In an alternate design (notshown) the liner 28 may be of uniform diameter except for an enlargedhead at the barrel bore end.

Referring to FIG. 2, the tool is now cocked and, as in the uncockedcondition shown in FIG. 1, the liner 28 retains the fastener coaxiallyaligned, its head being guided in the smooth bore of the liner 28 andthe washer W, if employed, being engaged by the liner muzzle end 40.This fastener supporting and guiding relation is maintained duringdriving. Following ignition of the charge the gas of combustion propelsthe ram 24 axially to impact the fastener head, and it is believed thata portion of the gas escapes at high velocity around the ram to advancein the barrel bore for reaction against a rear face of the liner headend 42. While the velocity relationship of the liner and the ram isunknown, it is believed that the liner 28 is axially driven at about thesame time as the ram. As a consequence, the liner muzzle end 40 thruststhe washer W toward the work piece while the liner bore axially guidesthe fastener head as it is driven by the ram. The fastener F is thuspreventing from wobbling and engaging the work piece P eccentrically.Accordingly, the fastener pointed end will, despite stiff resistance,penetrate the work piece and structure S with good efficiency and nodistortion or breakage. A five-eighths inch length fastener, forinstance, is thus enabled to be driven to full penetration in solidsteel without requiring extra power in a charge such as would berequired were the fastener to become askew as shown in FIG. 3.

While the fastener guiding influence of the washer W is usuallypreferred, it will be understood that the adapter line 28 isadvantageous in the guiding and driving of the headed and threadedfastener having no washer. The bore of the liner as it is driven axiallymaintains the fastener head aligned so that the fastener stem is keptsubstantially normal to the work piece during driving.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. An explosive fastener driving too] comprising a barrel having a borefor axially guiding a fastener driving ram, an adapter mounted on themuzzle end of the barrel for receiving a fastener to be driven by theram, and a tubular liner disposed for coaxial telescoping movementbetween the ram and the adapter, the bore of the liner being adapted toslidably support and guide at least one peripheral portion of thefastener as it is driven into a structure.

2. An explosive tool for driving washer-carrying headed fastenerscomprising a barrel, a muzzle adapter mounted on the barrel forreceiving a fastener to be driven, a ram axially slidable in the barrelbore for impacting the head of the fastener, and a liner axiallyslidable in the adapter while telescopingly accommodating a portion ofthe ram and the head of the fastener, an end of the liner being adaptedto bear on the washer endwise to stabilize the fastener during driving.

3. A tool as in claim 2 wherein a head end of the liner remote from afastener to be driven occupies the space between the adapter and the ramfor reaction to explosive gases bypassing the ram.

4. A tool as in claim 2 wherein means interconnects the adapter and theliner to permit them relative, limited longitudinal movement.

5. A tool as in claim 4 wherein said means comprises a longitudinal flatportion on the liner and a transverse pin mounted in the adapter partlyextendsfor relative movement along the flat portion.

1. An explosive fastener driving tool comprising a barrel having a borefor axially guiding a fastener driving ram, an adapter mounted on themuzzle end of the barrel for receiving a fastener to be driven by theram, and a tubular liner disposed for coaxial telescoping movementbetween the ram and the adapter, the bore of the liner being adapted toslidably support and guide at least one peripheral portion of thefastener as it is driven into a structure.
 2. An explosive tool fordriving washer-carrying headed fasteners comprising a barrel, a muzzleadapter mounted on the barrel for receiving a fastener to be driven, aram axially slidable in the barrel bore for impacting the head of thefastener, and a liner axially slidable in the adapter whiletelescopingly accommodating a portion of the ram and the head of thefastener, an end of the liner being adapted to bear on the washerendwise to stabilize the fastener during driving.
 3. A tool as in claim2 wherein a head end of the liner remote from a fastener to be drivenoccupies the space between the adapter and the ram for reaction toexplosive gases bypassing the ram.
 4. A tool as in claim 2 wherein meansinterconnects the adapter and the liner to permit them relative, limitedlongitudinal movement.
 5. A tool as in claim 4 wherein said meanscomprises a longitudinal flat portion on the liner and a transverse pinmounted in the adapter partly extends for relative movement along theflat portion.